Process for production of polyols with hydroxide containing double metal cyanide (DMC) Catalysts

ABSTRACT

The present invention provides process for producing polyols using a crystalline, hydroxide containing double metal cyanide (DMC) catalyst of the formulae (I) or (II), 
 
M 1   x [M 2 (CN) 6 ] y OH•L  (I) 
 
M 1   x [M 2 (CN) 6 ] y .zM 1 (OH) q •L  (II) 
 
wherein M 1  represents a metal selected from Zn +2 , Fe +2 , Ni +2 , Mn +2 , Co +2 , Sn +2 , Pb +2 , Fe +3 , Mo +4 , Mo +6 , Al +3 , V +4 , V +5 , Sr +2 , W +4 , W +6 , Cu +2  and Cr +3 , M 2  represents a metal selected from Fe +2 , Fe +3 , Co +2 , Co +3 , Cr +2 , Cr +3 , Mn +2 , Mn +3 , Ir +3 , Ni +2 , Rh +3 , Ru +2 , V +4  and V +5 , L represents an organic ligand and x, y and q are chosen to maintain electroneutrality. The polyols of the present invention may find use in the preparation of polyurethanes.

FIELD OF THE INVENTION

The present invention relates in general, to catalysis and catalysts,and more specifically, to a new class of crystalline, hydroxidecontaining DMC catalysts and polyols made therewith.

BACKGROUND OF THE INVENTION

Double metal cyanide (DMC) complexes are well known in the art forcatalyzing epoxide polymerization. Double metal cyanide (DMC) catalystsfor the polyaddition of alkylene oxides to starter compounds, which haveactive hydrogen atoms, are described, for example, in U.S. Pat. Nos.3,404,109, 3,829,505, 3,941,849 and 5,158,922. These active catalystsyield polyether polyols that have low unsaturation compared to similarpolyols made with basic (KOH) catalysis. The DMC catalysts can be usedto make many polymer products, including polyether, polyester, andpolyetherester polyols. The polyether polyols obtained with DMCcatalysts can be processed to form high-grade polyurethanes (e.g.,elastomers, foams, coatings and adhesives).

DMC catalysts are usually prepared by the reaction of an aqueoussolution of a metal salt with an aqueous solution of a metal cyanidesalt in the presence of an organic complexing ligand such as, forexample, an ether. In a typical catalyst preparation, aqueous solutionsof zinc chloride (in excess) and potassium hexacyanocobaltate are mixed,and dimethoxyethane (glyme) is subsequently added to the formedsuspension. After filtration and washing of the catalyst with aqueousglyme solution, an active catalyst of formula:Zn₃[Co(CN)₆]₂.xZnCl₂.yH₂O.zglymeis obtained.

Substantially amorphous DMC catalysts having exceptional activity forpolymerizing epoxides are described in U.S. Pat. No. 5,470,813. Comparedwith earlier DMC catalysts, the DMC catalysts described therein possessexcellent activity and produce polyether polyols with very lowunsaturation. The catalysts of the '813 patent are active enough toallow their use at very low concentrations, often low enough to overcomeany need to remove the catalyst from the polyol.

U.S. Pat. No. 4,477,589, issued to van der Hulst et al., teaches an acidmodified DMC catalyst prepared initially without organic complexingagent, by the addition of sodium hydroxide to precipitated zinchexacyanocobaltate to form the intermediate hydroxide salt of thegeneral formula:M¹ _(a)[M²(CN)_(b)(A)_(c)]_(d).pM¹(OH)_(q).yH₂OThis catalytically inactive intermediate is isolated and neutralized byHCl with and without glyme organic complexing agent. Ethers or glymesare the preferred organic activating agent. This patent further teachesthe use of Zn and Co in the presence of glyme, HCl, and ZnSO₄.

Combs et al., in U.S. Pat. No. 5,783,513, teach a process for makingsubstantially non-crystalline double metal cyanide (DMC) catalystshaving improved activity and performance. The process involves using ametal salt having an alkalinity within the range of about 0.2 to about2.0 wt. % as metal oxide based on the amount of metal salt to preparethe catalyst. This patent further teaches that important polyolproperties such as viscosity and unsaturation improve when thealkalinity of the metal salt used to make the DMC catalyst is properlycontrolled. A hydroxyl ligand is taught by Combs et al.

U.S. Pat. No. 5,627,122, issued to Le-Khac et al., teaches a crystallineDMC complex catalyst containing a DMC compound, an organic complexingagent, and a metal salt. The catalyst contains less than about 0.2 molesof the metal salt per mole of DMC compound; i.e., mole fractionZn/Co<1.6. Disclosed organic complexing agents include alcohols,aldehydes, ketones, ethers, esters, amides, ureas, nitrites, sulfides,and mixtures thereof. With low levels of ZnCl₂, these catalysts are veryactive and produce polyols with very low unsaturation. The metal salt ofLe-Khac contains chloride.

Combs, in U.S. Pat. No. 5,952,261, discloses highly active double metalcyanide complex catalysts useful for epoxide polymerization prepared byreacting zinc chloride or other metal salt with potassiumhexacyanocobaltate or other metal cyanide salt in the presence of aGroup IIA compound such as calcium chloride. The DMC catalyst of Combs'261 is amorphous and contains salts other than hydroxide.

Several patents and applications, in the name of Grosch et al.,including U.S. Pat. Nos. 6,303,533, 6,362,126, 6,303,833, and U.S. Pub.Pat. Appl. Nos. 2003/0013604, 2002/0032121, 2002/0006864 generallydisclose double-metal cyanide catalysts of the formula M¹_(a)[M²(CN)_(b)(A)_(c)]_(d).fM¹ _(g)X_(n).h(H₂O).eL, where M¹ is a metalion M² is a metal ion and M¹ and M² are identical or different, A is ananion, X is an anion, L is a water-miscible ligand, a, b, c, d, g and nare selected so as to make the compound electrically neutral, and edenotes the coordination number of the ligand, e and f denote fractionsor integers greater than or equal to zero, h denotes a fraction orinteger greater than or equal to zero. It appears the metal salt used inmaking the catalysts disclosed by Grosch must be water-soluble and thatmetal carboxylates are preferred.

A need exists in the art for a hydroxide containing double metal cyanide(DMC) catalyst and process for production of such a catalyst that doesnot require use of a water-soluble metal salt. Surprisingly, thecrystalline, double metal cyanide hydroxides of the present inventioncatalyze the polymerization of alkylene oxides whereas the compounds ofthe art do not.

SUMMARY OF THE INVENTION

The present invention provides a crystalline, hydroxide containingdouble metal cyanide (DMC) catalyst of the formulae (I) or (II),M¹ _(x)[M²(CN)₆]_(y)OH•L  (I)M¹ _(x)[M²(CN)₆]_(y).zM¹(OH)_(q)•L  (II)wherein M¹ represents a metal selected from the group consisting ofZn⁺², Fe⁺², Ni⁺², Mn⁺², Co⁺², Sn⁺², Pb⁺², Fe⁺³, Mo⁺⁴, Mo⁺⁶, Al⁺³, V⁺⁴,V⁺⁵, Sr⁺², W⁺⁴, W⁺⁶, Cu⁺² and Cr⁺³, M² represents a metal selected fromthe group consisting of Fe⁺², Fe⁺³, Co⁺², Co⁺³, Cr⁺², Cr⁺³, Mn⁺², Mn⁺³,Ir⁺³, Ni⁺², Rh⁺³, Ru⁺², V⁺⁴ and V⁺⁵, L represents an organic ligand, andx, y, and q are chosen to maintain electroneutrality.

Further provided, are processes for production of the crystalline,hydroxide containing DMC catalyst of the present invention and processesfor the preparation of polyols, in particular polyether polyols, withthe inventive crystalline, hydroxide containing DMC catalyst.

These and other advantages and benefits of the present invention will beapparent from the Detailed Description of the Invention herein below.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will now be described for purposes of illustrationand not limitation in conjunction with the following figures, wherein:

FIG. 1 depicts infrared spectrograms of selected DMC catalysts; and

FIG. 2 shows X-ray diffraction patterns of selected DMC catalysts.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described for purposes of illustrationand not limitation. Except in the operating examples, or where otherwiseindicated, all numbers expressing quantities, percentages, and so forthin the specification are to be understood as being modified in allinstances by the term “about.”

The present invention provides a crystalline, hydroxide containingdouble metal cyanide (DMC) catalyst of the formulae (I) or (II),M¹ _(x)[M²(CN)₆]_(y)OH•L  (I)M¹ _(x)[M²(CN)₆]_(y).zM¹(OH)_(q)•L  (II)M¹, in the above formula (I), represents a metal selected from Zn⁺²,Fe⁺², Ni⁺², Mn⁺², Co⁺², Sn⁺², Pb⁺², Fe⁺³, Mo⁺⁴, Mo⁺⁶, Al⁺³, V⁺⁴, V⁺⁵,Sr⁺², W⁺⁴, W⁺⁶, Cu⁺² and Cr⁺³. In the hydroxide containing DMC catalystof the present invention, Zn⁺² is particularly preferred as M¹.

M², in the above formula (I), represents a metal selected from Fe⁺²,Fe⁺³, Co⁺², Co⁺³, Cr⁺², Cr⁺³, Mn⁺², Mn⁺³, Ir⁺³, Ni⁺², Rh⁺³, Ru⁺², V⁺⁴V⁺⁵. In the hydroxide containing DMC catalyst of the present invention,Co⁺³ is particularly preferred as M².

Preferred organic complex ligands, L in the hydroxide containing DMCcatalyst of the present invention, include, but are not limited to,alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles,sulfides and mixtures thereof. More preferred as organic complex ligandsare water-soluble aliphatic alcohols such as ethanol, isopropanol,n-butanol, isobutanol, sec-butanol and tert-butanol, with tert-butanolbeing the most preferred.

In the above formulae (I) and (II), x, y, and q are selected so as tomaintain the electroneutrality of the hydroxide containing DMC complex.

The hydroxide containing DMC catalysts of the present invention may bemade by the steps of reacting a M¹ containing oxide or hydroxide with aM² containing hexacyanometallate or hexacyanometallic acid in thepresence of an organic ligand, L, and water, and collecting thecatalyst.

The hydroxide containing DMC catalysts of the present invention may bemade by the steps of reacting M¹ containing salts of some strong acids(such as sulfuric, sulfonic or nitrous acid) with a M² containinghexacyanometallate or hexacyanometallic acid in the presence of anorganic ligand, L, and water; and collecting the catalyst.

The hydroxide containing DMC catalysts of the present invention may bemade by the steps of reacting a M¹ containing oxide or hydroxide and aM¹ containing salt with a M² containing hexacyanometallate orhexacyanometallic acid in the presence of an organic ligand, L, andwater; and collecting the catalyst. The M¹ containing salt preferablycontains an anion selected from halides, sulfates, carbonates, cyanides,oxalates, thiocyanates, isocyanates, isothiocyanates, carboxylates andnitrates.

Alternatively, the hydroxide containing DMC catalysts of the presentinvention may be made by the steps of mixing a M¹ containing salt, astrongly basic compound (such as alkali metal hydroxides, alkaline earthmetal hydroxides, or amines) with a M² containing hexacyanometallate orhexacyanometallic acid in the presence of an organic ligand, L, andwater; and collecting the catalyst. The M¹ containing salt preferablycontains an anion selected from halides, sulfates, carbonates, cyanides,oxalates, thiocyanates, isocyanates, isothiocyanates, carboxylates andnitrates.

The metal containing oxide or hydroxide used in making the hydroxidecontaining DMC catalyst of the present invention may have a watersolubility ranging from low to almost water-insoluble. A preferred metalcontaining oxide is zinc oxide or zinc hydroxide.

The present invention is further illustrated, but is not to be limited,by the following examples.

EXAMPLES

Examples 1-7

A solution containing 0.54 moles of ligand (as noted in Table I below)and 275 g of distilled water was prepared in a four-neck, one-literflask equipped with a stirrer, thermocouple, and heating mantle. To thissolution was added 18.0 g (0.132 moles) of zinc chloride followed by3.30 g (0.033 moles) of zinc hydroxide. The slurry was heated to 50° C.with vigorous stirring. A syringe pump was used to add slowly 141 g of2.55% hexacyanocobaltic acid (H₃Co(CN)₆, 0.0165 moles) to the mixture.After the acid addition was completed, the mixture was heated andstirred for an additional 45 minutes. To this slurry was added 5 g of 1k diol and stirring was continued for two more minutes. The solid wascollected using a low-pressure stainless steel filtration unit. The wetcake was resuspended in 250 g of ligand and stirred at 50° C. for 60minutes. To this slurry was added 5 g of 1 k diol and stirring wascontinued for two more minutes. The solid was collected by pressurefiltration and dried overnight in a vacuum oven at 55° C.-60° C. Thecatalysts prepared in the above examples are summarized in Table I whereTBA refers to tert-butanol; IPA is isopropanol; PG is propylene glycoland PPG-425 is a 425 MW polypropylene glycol available from BayerPolymers LLC. TABLE I Example No. Ligand OH Peak FT-IR Comp. 1 waterNone 2 TBA 641 3 IPA 608 4 methyl ether PG 629 5 methyl ether PG 627 6PPG 425 None 7 1-propanol None

As can be appreciated by reference to Table I, catalysts 2-5 have a peakbetween 600 and 650 cm⁻¹. By reference to the infrared spectrogramsshown in FIG. 1, Catalyst A (made according to U.S. Pat. No. 5,482,908)and Catalyst B (made according to U.S. Pat. No. 5,783,513) exhibitedthis characteristic peak in the region around 642 cm⁻¹.

Typical peaks for OH rocking motions are found in the region between 500and 700 cm⁻¹ (I. Gennick and K. M. Harmon, Inorganic Chemistry, 14(9),2214, 1975). Catalyst C, in FIG. 1 (made according to van der Hulst etal., U.S. Pat. No. 4,477,589), had OH peaks at 3673 and 590-600 cm⁻¹ (J.Kuyper and G. Boxhoorn, Journal of Catalysis, 105, 163, 1987).

Examples 8-15

A solution containing 0.81 moles of ligand (as noted in Table II below),0.23 moles of zinc salt (anion as noted in Table II below), zinc oxide,and 200 g of distilled water was prepared in a four-neck, one-literflask equipped with a stirrer, thermocouple, and heating mantle. Thesolution was heated to 65° C. with vigorous stirring. A syringe pump wasused to add 266.3 g of 6.12% potassium hexacyanocobaltate (K₃Co(CN)₆,0.049 moles) to the mixture at 2.8 ml/min. After the addition wascomplete, the mixture was heated and stirred for an additional 45minutes. To this slurry was added 5 g of 1 k diol and the slurry wasstirred for two more minutes. The solid was collected using alow-pressure stainless steel filtration unit. The wet cake wasresuspended in 400 g of 90/10 wt/wt ligand/water solution and stirred at65° C. for 60 minutes. To this slurry was added 5 g of 1 k diol and theslurry was stirred for two more minutes. A second filtration wasperformed to collect the solid, which was dried overnight in a vacuumoven at 55° C.-60° C.

Table II summarizes the catalysts made in the above-detailed examples.TABLE II Ex. ZnO OH Peak cm⁻¹ No. Anion Ligand Added (Intensity)  8sulfate TBA No 640 (0.85)  9 sulfate IPA No 607 (0.31) 10 chloride TBANo 643 (0.06) 11 sulfonate TBA No 641 (0.53) 12 sulfonate TBA Yes 641(1.33) 13 sulfonate TBA Yes 641 (1.10) 14 chloride TBA Yes 640 (1.68) 15chloride glyme Yes 612 (1.27)

Addition of zinc oxide where sulfonates was used in Examples 12 and 13increases the intensity of the OH peaks in the resultant catalyst overthat of Example 11, a sulfonate where no zinc oxide was added.

Referencing FIG. 2, five characteristic peaks are found in thecrystalline x-ray diffraction pattern of zinc hexacyanocobaltatehydroxide between 12 and 26 2θ. The respective diffraction patterns forthe catalyst produced in Example 14, Example 2, Catalyst C from FIG. 1and zinc hexacyanocobaltate, are shown. Both of the inventive catalystsand Catalyst C showed all five of the peaks.

Example 16

2.0 g of 99.9% zinc oxide was dispersed in a solution of 686 g oft-butyl alcohol (TBA) and 54 g of deionized water in a one-liter flaskequipped with a stirrer and heating mantle. The slurry was heated to 55°C. before adding 39.5 g of an aqueous hexacyanocobaltic acid solution(0.17% cobalt) with a syringe pump over a 30 minute period. After allthe acid had been added, the slurry was mixed for 2 hours at 55° C. Themixture was filtered and the solid resuspended in 400 g of TBA andheated at 55° C. for 70 minutes. The slurry was filtered to collect thesolids that were dried in a vacuum oven overnight at 45° C.

The IR spectrum of this catalyst resembles that of Catalyst A, shown inFIG. 1, and contained the characteristic peak at about 642 cm⁻¹.Catalyst activity was assessed by making a 6 k triol with a four hourfeed at 126 ppm catalyst concentration as described below.

Catalyst Activity

Several of the catalysts made herein were evaluated for propoxylationactivity at 25 ppm by preparing a 6 k triol from a glycerine-based PO,block polyol having an OH number of 238 and a functionality of about 3.A reactor equipped with two six-inch pitched blade turbines, a Rushtonturbine at the bottom of the impeller shaft and baffles was used toprepare the polyol. Rates are calculated by monitoring drops in POpartial pressures from the moment oxide addition is completed. To reduceor eliminate mass transfer limitations between the liquid and vaporphases, the batch size is set such that the last blade is half coveredto encourage maximum interfacial mixing.

Calculated apparent rate constants (k_(app)) are used to calculate therelative rates shown in Table III below. These values were determined byplotting the natural logarithm of PO partial pressure versus time anddetermining the slope of the resultant straight line.

Table III summarizes the evaluations of several of the catalysts of thepresent invention. The control polyol was made with a catalyst accordingto Ex. 13 of U.S. Pat. No. 5,712,216. “Catalyst No.” refers to theexample number herein where the tested catalyst was prepared. As isapparent by reference to Table III, the inventive catalysts producedpolyols with comparable amounts of unsaturation as those produced usingthe catalysts of U.S. Pat. No. 5,712,216. TABLE III Catalyst RelativeViscosity No. Ligand rate* OH # Unsat'n (cPs) Control TBA 1 29 0.0051217 2 TBA 0.54 28.6 0.002 2694    2^(∓) TBA 0.43 28.7 0.003 1858 3 IPA0.18 28.7 0.008 16082*Rates normalized to 3 ppm cobalt in polyol.^(∓)Catalyst 2 at double the concentration.

The foregoing descriptions of the present invention are offered for thepurpose of illustration and not limitation. It will be apparent to thoseskilled in the art that the embodiments described herein may be modifiedor revised in various ways without departing from the spirit and scopeof the invention. The scope of the invention is to be measured by theappended claims.

1-25. (canceled)
 26. In a process for the production of a polyol bypolyaddition of an alkylene oxide to a starter compound containingactive hydrogen atoms, the improvement comprising conducting thepolyaddition in the presence of a crystalline, hydroxide containingdouble metal cyanide (DMC) catalyst of the formulae (I) or (II),M¹ _(x)[M²(CN)₆]_(y)OH•L  (I)M¹ _(x)[M²(CN)₆]_(y).zM¹(OH)_(z)•L  (II) wherein M¹ represents a metalselected from the group consisting of Zn⁺², Fe⁺², Ni⁺², Mn⁺², Co⁺²,Sn⁺², Pb⁺², Fe⁺³, Mo⁺⁴, Mo⁺⁶, Al⁺³, V⁺⁴, V⁺⁵, Sr⁺², W⁺⁴, W⁺⁶, Cu⁺² andCr⁺³, M² represents a metal selected from the group consisting of Fe⁺²,Fe⁺³, Co⁺², Co⁺³, Cr⁺², Cr⁺³, Mn⁺², Mn⁺³, Ir⁺³, Ni⁺², Rh⁺³, Ru⁺², V⁺⁴and V⁺⁵, L represents an organic ligand, and x, y and q are chosen tomaintain electroneutrality.
 27. The process according to claim 26,wherein the organic ligand, L, is selected from the group consisting ofalcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles,sulfides and mixtures thereof.
 28. The process according to claim 26,wherein the organic ligand, L, is selected from the group consisting ofethanol, isopropanol, n-butanol, isobutanol, sec-butanol andtert-butanol.
 29. The process according to claim 26, wherein M¹represents Zn⁺² and M² represents Co⁺³.
 30. The polyol made according tothe process of claim
 26. 31. In a process for the production of a polyolby polyaddition of an alkylene oxide to a starter compound containingactive hydrogen atoms, the improvement comprising conducting thepolyaddition in the presence of a crystalline, hydroxide containingdouble metal cyanide (DMC) catalyst of the formulae (I) or (II),M¹ _(x)[M²(CN)₆]_(y)OH•L  (I)M¹ _(x)[M²(CN)₆]_(y).zM¹(OH)_(q)•L  (II) wherein M¹ represents a metalselected from the group consisting of Zn⁺², Fe⁺², Ni⁺², Mn⁺², Co⁺²,Sn⁺², Pb⁺², Fe⁺³, Mo⁺⁴, Mo⁺⁶, Al⁺³, V⁺⁴, V⁺⁵, Sr⁺², W⁺⁴, W⁺⁶, Cu⁺² andCr⁺³, M² represents a metal selected from the group consisting of Fe⁺²,Fe⁺³, Co⁺², Co⁺³, Cr⁺², Cr⁺³, Mn⁺², Mn⁺³, Ir⁺³, Ni⁺², Rh⁺³, Ru⁺², V⁺⁴and V⁺⁵, L represents an organic ligand, and x, y and q are chosen tomaintain electroneutrality, the catalyst produced by, reacting a M¹containing oxide with a M² containing hexacyanometallate orhexacyanometallic acid in the presence of an organic ligand, L, andwater; and collecting the crystalline catalyst. 32-38. (canceled) 39.The process according to claim 31, wherein the organic ligand, L, isselected from the group consisting of alcohols, aldehydes, ketones,ethers, esters, amides, ureas, nitriles, sulfides and mixtures thereof.40. The process according to claim 31, wherein the organic ligand, L, isselected from the group consisting of ethanol, isopropanol, n-butanol,isobutanol, sec-butanol and tert-butanol.
 41. The process according toclaim 31, wherein M¹ represents Zn⁺² and M² represents Co⁺³.
 42. Thepolyol made according to the process of claim 31.